A conventional curtain wall is generally constructed by at least a vertical beam 1 and a horizontal beam 3; both beams 1, 3 linked together by a L-shaped bracket L and bolts B as shown in FIG. 8, which however has the following drawbacks:
1. The vertical and horizontal beams are not made for ventilating air in the curtain wall system so that other methods for ventilating the curtain wall should be further provided to increase installation cost, operation and maintenance problems for a building constructed by such a conventional curtain wall.
2. The whole curtain wall system including the vertical beams 1, the horizontal beams 3 and the L-shaped brackets L is lacking of measuring scale or means so that it should be carefully constructed and calibrated for its vertical or horizontal status, increasing construction inconvenience and installation labour cost.
3. The L-shaped bracket L having its horizontal leaf L1 secured to the horizontal beam 3 by a bolt B and having its vertical leaf L2 secured to the vertical beam 1 by the other bolt B may allow its horizontal leaf L1 to bear a great bending moment as loaded by the horizontal beam 3. If the strength or quality of the bracket L is not so good for durably supporting the horizontal beam, a fatigue failure of the bracket L may influence the construction safety of the whole building.
The present inventor has found the drawbacks of the conventional curtain wall and invented the present ventilable curtain wall.